Surufatinib plus toripalimab in patients with advanced solid tumors: a single-arm, open-label, phase 1 trial

PURPOSE: This phase 1 trial evaluated the safety, preliminary efficacy, and pharmacokinetics of surufatinib, a small molecular tyrosine kinase inhibitor, combined with toripalimab, a programmed cell death protein-1 antibody, in patients with advanced solid tumors. METHODS: This is an open-label, dose-escalation and expansion study in patients with solid tumors who had failed standard therapies or had no effective treatment. In the dose-escalation stage, patients were treated with surufatinib, at dose levels of 200, 250, or 300 mg once daily (QD) in combination with toripalimab 240 mg, every 3 weeks (Q3W), to estimate maximum tolerated dose. Additional patients were enrolled in the dose expansion stage to further assess the efficacy, safety, and pharmacokinetics profile. Recommended phase 2 dose (RP2D) was determined based on the safety, tolerability, and preliminary efficacy from dose-escalation and expansion stages. RESULTS: From Feb 14, 2019 to Dec 20, 2020, 33 patients were screened, of which 30 patients were enrolled. One patient in the 300 mg cohort experienced dose limited toxicity, a grade 3 hyperthyroidism. The most frequent treatment-related adverse events of grade ≥ 3 were hypertension (20.0%), transaminases increased (13.3%), and blood bilirubin increased (13.3%). No treatment-related death or treatment discontinuation was identified. The RP2D was determined to be surufatinib 250 mg QD plus toripalimab 240 mg Q3W. Objective response rate was 24.1% (95% confidence interval 10.3‒43.5%) in this study. CONCLUSIONS: Surufatinib plus toripalimab was well tolerated, with no unexpected safety signals, and showed preliminary anti-tumor activity in patients with advanced solid tumors. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT03879057; registration date: March 18, 2019. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00432-021-03898-8.